*Chatarunga means "four parts" and refers to the four parts of the Indian army: The boatmen, the cavalry, the elephant and the infantry.
My quote that you quoted is in response to @Batgirl assumption that it was a boat.
and @Ziryab assumption that it was a boat.
https://www.chess.com/forum/view/general/why-is-a-castle-called-a-rook?page=3#comment-89162375
My understanding is that it is a chariot. 車.
Your understanding that it is a chariot is based on glyphs from China (thousands of miles from where the game originated) dating from centuries after the game originated. Very unconvincing evidence. No chess/chaturanga pieces from the earliest centuries of the game in India survive, so what the original piece might have been cannot be determined with any great certainty. Whether the original piece was a chariot (as in much older Vedic texts concerning war in India) or a boat (much more common in Indian warfare--especially in the delta regions--at the time chaturanga originated) is unknown. Finally, you provide no link between the original Indian names for the pieces and modern English. What would be the relevance of anything you have said?
*Chatarunga means "four parts" and refers to the four parts of the Indian army: The boatmen, the cavalry, the elephant and the infantry.
My quote that you quoted is in response to @Batgirl assumption that it was a boat.
and @Ziryab assumption that it was a boat.
https://www.chess.com/forum/view/general/why-is-a-castle-called-a-rook?page=3#comment-89162375
My understanding is that it is a chariot. 車.
I said it was a boat in coastal parts of India. In other parts of India, it was a chariot. I made no assumption. I work from evidence.
I think H.J.R. Murray’s contention that the English rook is derived from a Persian word for chariot is the best answer to the OP’s question. At the same time, Murray’s claim is not without problems.
History is hard when evidence is thin. Vital is tolerance for ambiguity and recognition that we can only offer qualified possibilities without ever being certain. Murray does this well.
Batgirl also reads Murray.